Create advancedTranslate util

[marcustyphoon]

Description

Creates a utility function that, rather than returning only a single translated value for each root string as Tumblr's built-in helper does, returns all translated values associated with the root string including plurals and contexts with the same string. The utility falls back to tumblr.languageData if this extraction method breaks.

Testing steps

[marcustyphoon]

See also: #1461

[AprilSylph]

1. huh, i didn't see this one
2. oh hey you found the (output of) the *.po files, neat
3. i wonder how much lift it would be for me to add a new property to tumblr.languageData that just... has this... (i'm not working until next week, though)